Bent Up Cycles - SRAM etap blip box. Technically, you only need this and don't need the blips. But I have found that shifting with the blips by the brake levers works
How to Route Cables on Sram Red eTap Aero - YouTube
SRAM eTap AXS BlipBox - Components
eTap AXS Wireless Blips | EC-BLIP-B1 | SRAM
SRAM RED eTap BlipBox - Gateway Cycle | Oakdale, MN
Handmade Sram Etap Blips AXS Blips Buttons For TT Bike Dust and Waterproof Blipbox Remote Controller For RED AXS FORCE AXS